Studies show an increased prevalence of osteoporosis in individuals with chronic obstructive pulmonary disease (COPD), yet an understanding of the true prevalence, clinical implications, and mechanistic relationships remains limited. This proposal will determine the prevalence of decreased bone mineral density (BMD) and accelerated loss of BMD over time and its relationship to markers of bone resorption and formation within spirometrically defined categories of obstruction severity in a large cohort of current and former smokers with wide variability of airflow limitation. Radiographic, clinical, and serum marker phenotypes will be used to construct a classification and prediction model to identify COPD patients at greatest risk for osteoporosis and accelerated loss of BMD over time. Finally, a set of translational experiments will compare osteoclast formation and activity and its relationship to serum inflammatory mediators in COPD patients with and without decreased BMD and accelerated loss of BMD over time. These aims will define the COPD phenotype that should undergo osteoporosis screening, provide insight into the underlying mechanisms relating COPD and osteoporosis, and identify possible targets for screening and therapy. Training Plan: This proposal will provide the candidate with the unique opportunity to cross medical disciplines, expanding her COPD knowledge-base while developing a background in osteoporosis and bone metabolism. Through coursework and conferences, the candidate will acquire advanced training in biostatistics, epidemiology, and bioinformatics. Techniques learned in Dr. Roodman's laboratory through implementation of this proposal will equip the candidate with the skills necessary to communicate effectively during translational collaborations. The resources and experience of mentor Dr. Sciurba, an expert in COP clinical phenotyping and outcome assessment in clinical trials, and co-mentor Dr. Roodman, an authority on multiple myeloma and bone disease, combined with the robust research environment at the University of Pittsburgh, ensure the candidate's successful evolution to an independent investigator. (End of Abstract)